[gentoo-user] Xinerama vs TwinView for dual monitor setup

[gentoo-user] Xinerama vs TwinView for dual monitor setup

[Alan McKinnon]

Hi,

My notebook has this graphics hardware.

alan@nazgul ~ $ sudo lspci | grep VGA
01:00.0 VGA compatible controller: nVidia Corporation GeForce 8600M GT (rev 
a1)
alan@nazgul ~ $ sudo xdpyinfo | grep -A4 'screen #0'
screen #0:
  print screen:    no
  dimensions:    1920x1200 pixels (332x210 millimeters)
  resolution:    147x145 dots per inch
  depths (7):    24, 1, 4, 8, 15, 16, 32

I also have a second LCD monitor at work, a 1280x1024 that is physically 
slightly larger than the notebook screen, with a corresponding lower dpi.

I've configured it with TwinView to have the second monitor on the right, and 
how I usually use it is to put a user's support mail on that where I can read 
it and fix their issues using the tools on the main monitor. So it's a very 
unsophisticated setup, I have no need for massive 3D accel for eg games, or 
even for placing windows across two monitors. Windows are always on one 
screen or the other (because of the huge dpi difference). There are two 
smallish issues:

The viewports are aligned along the top edge and the 
panel/kicker/plasma/whatever on every desktop environment insists on trying 
to stretch across both monitors, into dead space on the right hand one. I'm 
getting use to right-click on panel, configure, set width to 57% at work, 
100% at home. If I align the viewports on the bottom edges, windows managers 
tend to want to position new windows with their title bars in the dead space 
at the top.

kdm and entrance want to stretch over both monitors. I definitely do not want 
this. Murphy dictates that all useful DM menus will end up in the dead space 
regardless of the theme I use <grrrr>

My research into nvidia's docs leads me to believe that TwinView is designed 
to make the presence of two physical monitors invisible and present one giant 
X screen, with a funky API for dead spaces (which may or may not work). I'm 
thinking Xinerama is the better option, despite the fact that it's old, 
clunky, hopeless at dealing with XRandR and can't be changed on the fly. I'm 
happy to set up two ServerLayouts to deal with this.

I'd appreciate some pros and cons feedback from the list before I embark on a 
huge emerge -e world to include Xinerama support.

-- 
alan dot mckinnon at gmail dot com

[gentoo-user] Re: Xinerama vs TwinView for dual monitor setup

[Grant Edwards]

On 2008-10-11, Alan McKinnon <alan.mckinnon@gmail.com> wrote:

> My research into nvidia's docs leads me to believe that TwinView is designed 
> to make the presence of two physical monitors invisible and present one giant 
> X screen, with a funky API for dead spaces (which may or may not work). I'm 
> thinking Xinerama is the better option, despite the fact that it's old, 
> clunky, hopeless at dealing with XRandR and can't be changed on the fly. I'm 
> happy to set up two ServerLayouts to deal with this.
>
> I'd appreciate some pros and cons feedback from the list before I embark on a 
> huge emerge -e world to include Xinerama support.

There's a third option you haven't mentioned: two different
displays rather than a large virtual display spread across two
monitors.  After reading up on the options, it's what I chose
to do.

Cons:

  * You can't drag a window from one display to the other.
  
  * Windows can't overlap from one display to the other.  

  * 3D HW accel and HW video overlay only available on one of
    the displays.  

Pros: 

  * Mouse movement and focus still act like one large display.

  * Each display can have it's own set of virtual desktops and
    they can be switched indpendantly.

  * Things like window-manager panels/docs/taskbars are managed
    separately for the two displays.

  * Displays can have different resolutions, sizes, depths.    

I particularly like having multiple virtual desktops for each
display and being able to independanly toggle the displays
among their virtual desktops.  Once in a while I wish I could
drag a window from one display to the other, but not very
often.
    
-- 
Grant

Re: [gentoo-user] Re: Xinerama vs TwinView for dual monitor setup

[Alan McKinnon]

On Sunday 12 October 2008 00:36:17 Grant Edwards wrote:
> On 2008-10-11, Alan McKinnon <alan.mckinnon@gmail.com> wrote:
> > My research into nvidia's docs leads me to believe that TwinView is
> > designed to make the presence of two physical monitors invisible and
> > present one giant X screen, with a funky API for dead spaces (which may
> > or may not work). I'm thinking Xinerama is the better option, despite the
> > fact that it's old, clunky, hopeless at dealing with XRandR and can't be
> > changed on the fly. I'm happy to set up two ServerLayouts to deal with
> > this.
> >
> > I'd appreciate some pros and cons feedback from the list before I embark
> > on a huge emerge -e world to include Xinerama support.
>
> There's a third option you haven't mentioned: two different
> displays rather than a large virtual display spread across two
> monitors.  After reading up on the options, it's what I chose
> to do.
>
> Cons:
>
>   * You can't drag a window from one display to the other.

This is pretty much a requirement for how I like to do things at work

The rest of your pros and cons either suit me just fine or don't feature at 
all. As for multiple desktops on a screen, I would just dispend with this.

The one thing I really do want to do is launch a reply window from kmail and 
drag it to the second monitor, where I use it like it was a big sticky note 
scratch-pad. I do the same thing with wiki pages, pdfs and other reference 
docs while working on the main monitor (which itself tends have many windows 
open on it).

I don't think I would be able to do this with your setup, please correct me if 
I'm wrong?

-- 
alan dot mckinnon at gmail dot com

[gentoo-user] Re: Xinerama vs TwinView for dual monitor setup

[Grant Edwards]

On 2008-10-12, Alan McKinnon <alan.mckinnon@gmail.com> wrote:

>> Cons:
>>
>>   * You can't drag a window from one display to the other.
>
> This is pretty much a requirement for how I like to do things
> at work

Two displays is probably not an option for you.

> The rest of your pros and cons either suit me just fine or
> don't feature at all. As for multiple desktops on a screen, I
> would just dispend with this.

I guess I don't know how anybody can get along conveniently
with just one desktops.  Perhaps other people don't get
interrupted while working on one task and have to switch to a
different task.  Once I've got a desktop set up for the task at
hand, I find it much easier to switch to a new desktop when I
need to open up a bunch of new windows/programs to handle an
interruption.

> The one thing I really do want to do is launch a reply window
> from kmail and drag it to the second monitor, where I use it
> like it was a big sticky note scratch-pad. I do the same thing
> with wiki pages, pdfs and other reference docs while working
> on the main monitor (which itself tends have many windows 
> open on it).

That's what I do: I usually have PDF documents, e-mails, web
pages, etc. open on one screen while I work on code on the
other. At other times I have code and build windows on one
display and test-driver programs on the other.

But, Instead of dragging things from one monitor to the other, I
just open them where I want them.

> I don't think I would be able to do this with your setup,
> please correct me if I'm wrong?

I'm not entirely sure what "this" is.  I usually know where I'm
going to want a window and I open on the appropriate display.

-- 
Grant

Re: [gentoo-user] Re: Xinerama vs TwinView for dual monitor setup

[Iain Buchanan]

Grant Edwards wrote:
[snip]
>
> There's a third option you haven't mentioned: two different
> displays rather than a large virtual display spread across two
> monitors.

[snip]

> Pros:
>
>    * Mouse movement and focus still act like one large display.
>
>    * Each display can have it's own set of virtual desktops and
>      they can be switched indpendantly.

Really?  When I set up separate X screens, changing virtual desktops on 
one display (eg from "VD1" to "VD2") also changed it on the other display.

>    * Things like window-manager panels/docs/taskbars are managed
>      separately for the two displays.
>
>    * Displays can have different resolutions, sizes, depths.

So can xinerama / twinview :)

-- 
Iain Buchanan <iaindb at netspace dot net dot au>

When things go well, expect something to explode, erode, collapse or
just disappear.

[gentoo-user] Re: Xinerama vs TwinView for dual monitor setup

[Grant Edwards]

On 2008-10-13, Iain Buchanan <iaindb@netspace.net.au> wrote:
> Grant Edwards wrote:
> [snip]
>>
>> There's a third option you haven't mentioned: two different
>> displays rather than a large virtual display spread across two
>> monitors.
>
> [snip]
>
>> Pros:
>>
>>    * Mouse movement and focus still act like one large display.
>>
>>    * Each display can have it's own set of virtual desktops and
>>      they can be switched indpendantly.
>
> Really?  When I set up separate X screens, changing virtual desktops on 
> one display (eg from "VD1" to "VD2") also changed it on the other display.

It probably depends on your window manager.  I'm using XFCE,
and switching "workspaces" as they're called in XFCE is
independant for the two displays.

>>    * Things like window-manager panels/docs/taskbars are managed
>>      separately for the two displays.
>>
>>    * Displays can have different resolutions, sizes, depths.
>
> So can xinerama / twinview :)

I thought I had read somewhere that they had to have the same
depth at least.

-- 
Grant Edwards                   grante             Yow! I'm having fun
                                  at               HITCHHIKING to CINCINNATI
                               visi.com            or FAR ROCKAWAY!!

[gentoo-user] Re: Xinerama vs TwinView for dual monitor setup

[Grant Edwards]

On 2008-10-13, Grant Edwards <grante@visi.com> wrote:

>>>    * Displays can have different resolutions, sizes, depths.
>>
>> So can xinerama / twinview :)
>
> I thought I had read somewhere that they had to have the same
> depth at least.

Based on what little I do know about Xlib I'm also pretty
surprised that a window can span two displays that have
different resolutions (DPI).

-- 
Grant Edwards                   grante             Yow! ... he dominates the
                                  at               DECADENT SUBWAY SCENE.
                               visi.com            

Re: [gentoo-user] Xinerama vs TwinView for dual monitor setup

[YoYo siska]

On Sat, Oct 11, 2008 at 11:34:10PM +0200, Alan McKinnon wrote:
> Hi,
> 
> My notebook has this graphics hardware.
> 
> alan@nazgul ~ $ sudo lspci | grep VGA
> 01:00.0 VGA compatible controller: nVidia Corporation GeForce 8600M GT (rev 
> a1)
> alan@nazgul ~ $ sudo xdpyinfo | grep -A4 'screen #0'
> screen #0:
>   print screen:    no
>   dimensions:    1920x1200 pixels (332x210 millimeters)
>   resolution:    147x145 dots per inch
>   depths (7):    24, 1, 4, 8, 15, 16, 32
> 
> I also have a second LCD monitor at work, a 1280x1024 that is physically 
> slightly larger than the notebook screen, with a corresponding lower dpi.
> 
> I've configured it with TwinView to have the second monitor on the right, and 
> how I usually use it is to put a user's support mail on that where I can read 
> it and fix their issues using the tools on the main monitor. So it's a very 
> unsophisticated setup, I have no need for massive 3D accel for eg games, or 
> even for placing windows across two monitors. Windows are always on one 
> screen or the other (because of the huge dpi difference). There are two 
> smallish issues:
> 
> The viewports are aligned along the top edge and the 
> panel/kicker/plasma/whatever on every desktop environment insists on trying 
> to stretch across both monitors, into dead space on the right hand one. I'm 
> getting use to right-click on panel, configure, set width to 57% at work, 
> 100% at home. If I align the viewports on the bottom edges, windows managers 
> tend to want to position new windows with their title bars in the dead space 
> at the top.

You probably haven't emerged the applications with Xinerama support.
This is especially true for kde 3. Twinview uses the xinerama protocol
(well,its an extension of the X protocol... ;) to inform applications
about the layout of monitors. 
> 
> kdm and entrance want to stretch over both monitors. I definitely do not want 
> this. Murphy dictates that all useful DM menus will end up in the dead space 
> regardless of the theme I use <grrrr>
> 
> My research into nvidia's docs leads me to believe that TwinView is designed 
> to make the presence of two physical monitors invisible and present one giant 
> X screen, with a funky API for dead spaces (which may or may not work). I'm 
> thinking Xinerama is the better option, despite the fact that it's old, 
> clunky, hopeless at dealing with XRandR and can't be changed on the fly. I'm 
> happy to set up two ServerLayouts to deal with this.

As I said, twinview uses the xinerama protocol to inform apps about the
monitors, so there wouldn't be any difference in the way applications
behave.  You would only loose the  advantages of twinview (you can look
at it as an enhanced, nvidia only, in-driver version of xinerama)

Even xrandr 1.2 provides xinerama style info for the applications, so
you certainly want your application to be compiled with xinerama
support, independently of the way you set up the X server.

BTW in my experince kde compiled without xinerama supp. handles multiple
(independent) screens O, but not xinerama (well, that could be
expected), and with xinerama support it handles xinerama ok, but fails
with independent screen ;)

> I'd appreciate some pros and cons feedback from the list before I embark on a 
> huge emerge -e world to include Xinerama support.
> 
> -- 
> alan dot mckinnon at gmail dot com
> 
> 

yoyo

-- 
      _
      |            
YoYo () Siska      
===================
http://www.ksp.sk/

Re: [gentoo-user] Xinerama vs TwinView for dual monitor setup

[Iain Buchanan]

Alan McKinnon wrote:
> Hi,
>
> My notebook has this graphics hardware.
>
> alan@nazgul ~ $ sudo lspci | grep VGA
> 01:00.0 VGA compatible controller: nVidia Corporation GeForce 8600M GT (rev
> a1)

I have a Quadro FX 1600M, using nvidia-drivers...

> I also have a second LCD monitor at work, a 1280x1024 that is physically
> slightly larger than the notebook screen, with a corresponding lower dpi.

... I have an LCD at 1920x1200, but it's much larger than my laptop 
display, so the dpi is different.  So far I have no working way of 
setting different DPI's on the different monitors.

[snip]

> I've configured it with TwinView

as in:
      Option         "TwinView" "True"
?

> The viewports are aligned along the top edge

you mean move the mouse up and it appears on the next screen?  Don't you 
want them aligned left / right of each other?

>  and the
> panel/kicker/plasma/whatever on every desktop environment insists on trying
> to stretch across both monitors, into dead space on the right hand one.

Sounds like you haven't compiled stuff with the xinerama USE flag.  I 
put it in make.conf, and then did a emerge --newuse.

> I'm
> getting use to right-click on panel, configure, set width to 57% at work,
> 100% at home. If I align the viewports on the bottom edges, windows managers
> tend to want to position new windows with their title bars in the dead space
> at the top.

definitely sounds like you haven't recompiled with xinerama.

> kdm and entrance want to stretch over both monitors. I definitely do not want
> this. Murphy dictates that all useful DM menus will end up in the dead space
> regardless of the theme I use<grrrr>

xinerama should make your wm open screens on one window only.  Also your 
log-in screen should be on one screen only, and panels should be on one 
screen only.

> My research into nvidia's docs leads me to believe that TwinView is designed
> to make the presence of two physical monitors invisible and present one giant
> X screen, with a funky API for dead spaces (which may or may not work). I'm
> thinking Xinerama is the better option, despite the fact that it's old,
> clunky, hopeless at dealing with XRandR and can't be changed on the fly. I'm
> happy to set up two ServerLayouts to deal with this.
>
> I'd appreciate some pros and cons feedback from the list before I embark on a
> huge emerge -e world to include Xinerama support.

Why would you do -e world?  How about `emerge -uN world` The N being 
--newuse.  or `emerge -vauDN world`.

It's not that huge, but you need it regardless of whether you use 
twinview or xinerama anyway.

$ equery hasuse xinerama | wc -l
16

check out my blog for how I did it:

http://nthrbldyblg.blogspot.com/2008/08/nvidia-xinerama-on-dell-m6300.html

HTH,
-- 
Iain Buchanan <iaindb at netspace dot net dot au>

Chuck Norris once ate a whole cake before his friends could tell him 
there was a stripper in it.

Re: [gentoo-user] Xinerama vs TwinView for dual monitor setup

[Alan McKinnon]

On Monday 13 October 2008 04:02:19 Iain Buchanan wrote:

> [snip]
>
> > I've configured it with TwinView
>
> as in:
>       Option         "TwinView" "True"

Yes. Some output :

$ sudo grep -i -e xinerama -e twinview /var/log/Xorg.0.log
(**) Option "Xinerama" "1"
(**) Xinerama: enabled
(**) NVIDIA(0): Option "TwinView" "1"
(**) NVIDIA(0): Option "TwinViewXineramaInfoOrder" "DFP-0"
(**) NVIDIA(0): TwinView enabled
(II) Initializing built-in extension XINERAMA

$ sudo grep -i -e xinerama -e twinview /etc/X11/xorg.conf
        Option          "Xinerama"      "1"
        Option          "TwinView"              "1"
        Option          "TwinViewXineramaInfoOrder"     "DFP-0"


> > The viewports are aligned along the top edge
>
> you mean move the mouse up and it appears on the next screen?  Don't you
> want them aligned left / right of each other?

My description wasn't clear. I mean the screens are physically and logically 
laid out like so:

+------------------------------+
|                  |           |
|        1         |     2     |
|                  |-----------+
+------------------+

1 is the notebook screen
2 is the external lcd
below 2 is dead space. The mouse works correctly.

> >  and the
> > panel/kicker/plasma/whatever on every desktop environment insists on
> > trying to stretch across both monitors, into dead space on the right hand
> > one.
>
> Sounds like you haven't compiled stuff with the xinerama USE flag.  I
> put it in make.conf, and then did a emerge --newuse.

OK, I did that. The packages that got rebuilt are:

$ equery hasuse xinerama
[ Searching for USE flag xinerama in all categories among: ]
 * installed packages
[I--] [ ~] x11-apps/xdpyinfo-1.0.3 (0)
[I--] [ ~] x11-libs/qt-3.3.8b (3)
[I--] [ ~] x11-libs/gtk+-2.14.3-r2 (2)
[I--] [ ~] x11-libs/qt-gui-4.4.2 (4)
[I--] [  ] x11-misc/engage-9999 (0)
[I--] [ ~] kde-base/ksplash-4.1.2 (4.1)
[I--] [ ~] kde-base/plasma-workspace-4.1.2 (4.1)
[I--] [ ~] kde-base/ksplashml-3.5.10 (3.5)
[I--] [ ~] kde-base/systemsettings-4.1.2 (4.1)
[I--] [ ~] kde-base/kwin-4.1.2 (4.1)
[I--] [ ~] kde-base/libplasma-4.1.2 (4.1)
[I--] [ ~] kde-misc/knetworkmanager-0.2.2_p20080528 (0)
[I--] [ ~] kde-misc/filelight-1.0-r1 (0)
[I--] [  ] media-libs/libsdl-1.2.13 (0)
[I--] [  ] media-libs/xine-lib-1.1.15-r1 (1)
[I--] [  ] net-libs/xulrunner-1.8.1.17 (1.8)
[I--] [ ~] media-sound/kid3-1.0 (0)
[I--] [ ~] media-sound/amarok-1.4.10-r1 (0)
[I--] [ ~] media-video/mplayer-1.0_rc2_p27725-r1 (0)
[I--] [  ] media-video/xine-ui-0.99.5-r1 (0)
[I--] [ ~] media-video/gxine-0.5.903 (0)
[I--] [ ~] app-cdr/k3b-1.0.5-r3 (0)


Seems like the only things that would affect kde-3 apps is qt-3.3.8b.
Plus x11-libs/libXinerama and x11-proto/xineramaproto (both latest unstable) 
are installed.

[snip]

> > I'd appreciate some pros and cons feedback from the list before I embark
> > on a huge emerge -e world to include Xinerama support.
>
> Why would you do -e world?  How about `emerge -uN world` The N being
> --newuse.  or `emerge -vauDN world`.

I was running 
/bin/think --exaggerate --frustrated --logic-level -3
when I typed that :-)

> check out my blog for how I did it:
>
> http://nthrbldyblg.blogspot.com/2008/08/nvidia-xinerama-on-dell-m6300.html

Nice blog :-)

I'll fiddle some more with these tips later in the day, but first a conceptual 
question: I read that huge collection of docs from nvidia-drivers, and 
concluded that Xinerama and TwinView are fundamentally different and 
incompatible. i.e. Xinerama starts with two classic X screens and joins them 
in software to make one big display - an abstraction layer if you will. 
TwinView rips out the guts of X, dispenses with the notion of separate 
screens for a TwinView display and gives you one giant screen with no API for 
an app to see how this big screen is composed. So, you either use Xinerama or 
TwinView, but not both.

Obviously, this understanding of mine is flawed. Which bit did I get wrong?

-- 
alan dot mckinnon at gmail dot com

Re: [gentoo-user] Xinerama vs TwinView for dual monitor setup

[YoYo siska]

On Mon, Oct 13, 2008 at 09:10:34AM +0200, Alan McKinnon wrote:
> On Monday 13 October 2008 04:02:19 Iain Buchanan wrote:
> 
> > [snip]
> >
> > > I've configured it with TwinView
> >
> > as in:
> >       Option         "TwinView" "True"
> 
> Yes. Some output :
> 
> $ sudo grep -i -e xinerama -e twinview /var/log/Xorg.0.log
> (**) Option "Xinerama" "1"
> (**) Xinerama: enabled
> (**) NVIDIA(0): Option "TwinView" "1"
> (**) NVIDIA(0): Option "TwinViewXineramaInfoOrder" "DFP-0"
> (**) NVIDIA(0): TwinView enabled
> (II) Initializing built-in extension XINERAMA
> 
> $ sudo grep -i -e xinerama -e twinview /etc/X11/xorg.conf
>         Option          "Xinerama"      "1"
>         Option          "TwinView"              "1"
>         Option          "TwinViewXineramaInfoOrder"     "DFP-0"
> 
> 
> > > The viewports are aligned along the top edge
> >
> > you mean move the mouse up and it appears on the next screen?  Don't you
> > want them aligned left / right of each other?
> 
> My description wasn't clear. I mean the screens are physically and logically 
> laid out like so:
> 
> +------------------------------+
> |                  |           |
> |        1         |     2     |
> |                  |-----------+
> +------------------+
> 
> 1 is the notebook screen
> 2 is the external lcd
> below 2 is dead space. The mouse works correctly.
> 
> > >  and the
> > > panel/kicker/plasma/whatever on every desktop environment insists on
> > > trying to stretch across both monitors, into dead space on the right hand
> > > one.
> >
> > Sounds like you haven't compiled stuff with the xinerama USE flag.  I
> > put it in make.conf, and then did a emerge --newuse.
> 
> OK, I did that. The packages that got rebuilt are:
> 
> $ equery hasuse xinerama
> [ Searching for USE flag xinerama in all categories among: ]
>  * installed packages
> [I--] [ ~] x11-apps/xdpyinfo-1.0.3 (0)
> [I--] [ ~] x11-libs/qt-3.3.8b (3)
> [I--] [ ~] x11-libs/gtk+-2.14.3-r2 (2)
> [I--] [ ~] x11-libs/qt-gui-4.4.2 (4)
> [I--] [  ] x11-misc/engage-9999 (0)
> [I--] [ ~] kde-base/ksplash-4.1.2 (4.1)
> [I--] [ ~] kde-base/plasma-workspace-4.1.2 (4.1)
> [I--] [ ~] kde-base/ksplashml-3.5.10 (3.5)
> [I--] [ ~] kde-base/systemsettings-4.1.2 (4.1)
> [I--] [ ~] kde-base/kwin-4.1.2 (4.1)
> [I--] [ ~] kde-base/libplasma-4.1.2 (4.1)
> [I--] [ ~] kde-misc/knetworkmanager-0.2.2_p20080528 (0)
> [I--] [ ~] kde-misc/filelight-1.0-r1 (0)
> [I--] [  ] media-libs/libsdl-1.2.13 (0)
> [I--] [  ] media-libs/xine-lib-1.1.15-r1 (1)
> [I--] [  ] net-libs/xulrunner-1.8.1.17 (1.8)
> [I--] [ ~] media-sound/kid3-1.0 (0)
> [I--] [ ~] media-sound/amarok-1.4.10-r1 (0)
> [I--] [ ~] media-video/mplayer-1.0_rc2_p27725-r1 (0)
> [I--] [  ] media-video/xine-ui-0.99.5-r1 (0)
> [I--] [ ~] media-video/gxine-0.5.903 (0)
> [I--] [ ~] app-cdr/k3b-1.0.5-r3 (0)

tabletka ~ # equery hasuse xinerama | wc -l
285

most of them are apps from kde-base/* (3.5.9), seems that it changed between
3.5.9 and 3.5.10, plus iwndow managers like fluxbox, openbox... 

> 
> Seems like the only things that would affect kde-3 apps is qt-3.3.8b.
> Plus x11-libs/libXinerama and x11-proto/xineramaproto (both latest unstable) 
> are installed.
> 
> [snip]
> 
> > > I'd appreciate some pros and cons feedback from the list before I embark
> > > on a huge emerge -e world to include Xinerama support.
> >
> > Why would you do -e world?  How about `emerge -uN world` The N being
> > --newuse.  or `emerge -vauDN world`.
> 
> I was running 
> /bin/think --exaggerate --frustrated --logic-level -3
> when I typed that :-)
> 
> > check out my blog for how I did it:
> >
> > http://nthrbldyblg.blogspot.com/2008/08/nvidia-xinerama-on-dell-m6300.html
> 
> Nice blog :-)
> 
> I'll fiddle some more with these tips later in the day, but first a conceptual 
> question: I read that huge collection of docs from nvidia-drivers, and 
> concluded that Xinerama and TwinView are fundamentally different and 
> incompatible. i.e. Xinerama starts with two classic X screens and joins them 
> in software to make one big display - an abstraction layer if you will. 
> TwinView rips out the guts of X, dispenses with the notion of separate 
> screens for a TwinView display and gives you one giant screen with no API for 
> an app to see how this big screen is composed. So, you either use Xinerama or 
> TwinView, but not both.
> 
> Obviously, this understanding of mine is flawed. Which bit did I get wrong?

Xinerama consists basically of two parts, the protocol to communicate the
position/sizes of screen between the Xserver and the applications (which
you usually get by enabling the xinerama use flag) and an xserver part
(module?) that you can use to set up the screens. What you said is
correct for the Xserver setup part...
You use either xinerama setup to put together completely different
displays (might be different cards, such as one nvidia, one ati, ...) 
or twinview in case of a dualhead nvidia setup. But both this setups use
the xinerama protocol to let the apps/wm know the placement of the monitors.
> 
> -- alan dot mckinnon at gmail dot com
> 
> 

-- 
      _
      |            
YoYo () Siska      
===================
http://www.ksp.sk/

Re: [gentoo-user] Xinerama vs TwinView for dual monitor setup

[Alan McKinnon]

On Monday 13 October 2008 13:53:49 YoYo siska wrote:
> tabletka ~ # equery hasuse xinerama | wc -l
> 285
>
> most of them are apps from kde-base/* (3.5.9), seems that it changed
> between 3.5.9 and 3.5.10, plus iwndow managers like fluxbox, openbox...

That looks better. I was convinced that most kde-3 apps had a xinerama USE 
flag, hence my 'emerge -e world' comment that Iain picked up on. 

I wonder why it was changed for KDE-3.5.10, it seems that Xinerama support is 
now automatically built for most of KDE-3 (deduced by examining the ebuild 
and ldd output)

> > Obviously, this understanding of mine is flawed. Which bit did I get
> > wrong?
>
> Xinerama consists basically of two parts, the protocol to communicate the
> position/sizes of screen between the Xserver and the applications (which
> you usually get by enabling the xinerama use flag) and an xserver part
> (module?) that you can use to set up the screens. What you said is
> correct for the Xserver setup part...

> You use either xinerama setup to put together completely different
> displays (might be different cards, such as one nvidia, one ati, ...)
> or twinview in case of a dualhead nvidia setup. But both this setups use
> the xinerama protocol to let the apps/wm know the placement of the
> monitors.

<penny drops>

OK, so there's a xinerama protocol and a xinerama lib and these are not the 
same thing

</penny drops>

-- 
alan dot mckinnon at gmail dot com